The problem is, the mage says "Ok, I'll cast Identify." Suddenly, the DM is faced with an issue. The spell tells the party what the sword is. The sword, as an item, is exactly a +2 Adamantine Longsword. The problem is, that is exactly what goes down on the loot sheet. The party fighter will take the sword you just lovingly described, and write it down exactly as a +2 Adamantine Longsword. Next week/month/whatever, when you play the next session, no one will remember what the sword looks like or feels like.
I like to tackle this issue in two ways. The first one is to make even the exact, standard description mysterious. And I do this by making the items not entirely beneficial. I wrote about this back at the beginning of August:
This is one area where most games, pen-and-paper RPGs and, most especially, computer RPGs alike, almost all stumble, and in the exact same way. By making magic predictable, reliable, and easily controllable, they drain all the color from it. Fireballs not only harm just your enemies, they don’t cause fires to break out or melt the treasure the monsters were carrying. Stored magical power doesn’t leak or cause unexpected effects. Magic is far more reliable and boring than technology; your computer might blue-screen, your light bulbs might pop, and your car may be melting the polar icecaps, but your wand of lightning bolts only ever does 6d6 points of damage to your intended targets.
When you can't trust magic, when you know in advance there will be a cost for using it, it becomes not just another stat bonus, but instead a resource to be used with caution and treated with respect.
That, however, doesn't really address the issue David is talking about here. Why should players be interested in the description of the magical items, their flavor and style? One general rule applies any time you want the players to pay attention to something: if you want them to care, you have to make it important.
History does not always repeat itself. Sometimes it just yells "Can't you remember anything I told you?" and lets fly with a club.- John W. Campbell
If you want the players to care that the mithril blade was forged by the famed elven smith Norenvyll, then have a collector offer them more than it's market value for the blade. If you want them to care that the Battle of Kessnal Ford was won when an elven champion used this same sword to behead the orcish chieftain Chugrel, have Chugrel's half-orcish daughters assume one of the PCs was that hero when they see him with it in a tavern. Do they want vengeance? Or do they believe the sword has stolen their father's soul, and must be destroyed so his spirit can pass on to the Outer Planes? Or do they owe a debt of fealty to the wielder of the blade, for freeing their mother from the cruel warlord?
You can even have NPCs react to how things look. Even though it wasn't magical, the armour of Sturm from the Dragonlance novels got a reaction from almost everyone who saw it and recognized its significance. What sort of reaction do elves or dwarves have to someone wearing a sword crafted in the elven style? Does that reaction change if the sword was actually crafted by a human smith aping the elvish style? Does the priesthood of the Moon treat differently those who wear the sacred metal silver? Does wearing white, doeskin boots of speed before the Feastday of St. Peret of the Stonemasons get you snickered at in the courts of the High King?
Yeah, you can really go overboard with this, and it only works if your players are interested in these sorts of anthropological details. Still, I've not yet known a player to pass over even a +1 reaction bonus if all they need to do is change out their usual +2 bastard sword for the +1, +2 vs. lycanthropes they've been storing in the bag of holding.